They were brought to a hospital, although their conditions were unknown.

The same police report, however, was unclear who carried out the attack, which occurred on Monday evening on the eve of the town’s Catholic feast.

No individual or group claimed responsibility for the explosion that also left two civilians—Leonardo de la Peña and Jetphonie Navales—wounded.

An investigation into the blast was immediately launched to determine whether rebels or jihadist groups were involved in the attack.

The assault coincided with continuing military operations against the jihadist group of Abdullah Maute and New People’s Army (NPA) rebels. Maute’s group had previously beheaded four people in Sarangani and Lanao del Sur provinces, where they are actively operating.

The province is also a lair of rebels from the larger Moro Islamic Liberation Front, which signed an interim peace deal with the government in 2014.